Factual error: When Kersey finds his throw down gun and proceeds to practice with it, a bullet ricochets back at him. Lead will reflect off objects and continue in the same general direction or flatten out on a surface but will not bounce back at you. If it did, indoor shooting ranges would kill all of their patrons on a daily basis.
Factual error: When Dr. Paul Kersey pays a visit to Joe Gannon, the garage mechanic, Kersey slices open Gannon's leg with a scalpel, then pours automotive brake fluid into the wound. The brake fluid sizzles and foams on contact with the blood, which is chemically impossible. Brake fluid is simply hydraulic fluid formulated for extreme temperatures. The diethylene glycol in brake fluid may be toxic and may sting slightly in open wounds, but it does not violently react with blood and sizzle like acid as depicted in this film. (01:14:45)
